When will most games use 4 cores?

Solution
Probably not until after the next generation of consoles hits late next year and the lowest common denominator for game development is raised as a result. As long as most games are designed to run on the aging XBox 360, there isn't much need for that much CPU power for most games. Most of the games that do have decent support for more than 2 cores are the few titles that were designed more for PC first and then got cut down to work on the consoles.
Probably not until after the next generation of consoles hits late next year and the lowest common denominator for game development is raised as a result. As long as most games are designed to run on the aging XBox 360, there isn't much need for that much CPU power for most games. Most of the games that do have decent support for more than 2 cores are the few titles that were designed more for PC first and then got cut down to work on the consoles.
 
Solution
The reality is, There are only 2 to 3 primary uses for the CPU for gaming. It is far easier for developers to write their code to only use 2-3 processes, which end up on 2-3 cores. Using more takes far more work, and most developers will not go through the extra work needed to use more than 2 or 3 cores.
 
I did hear Epic Games (company responsible for unreal tournament) has been saying that by 2017 they expect to finish their new project (games running on 20+ CPU cores), and that those will be mostly used to calculate muscle movement.

I dotn know if it was just marketing, but generally Epic Games does come throu with their promises.

As for your question, i think Supernova go it Aced.